The present invention relates to a recording apparatus for recording information in a recording medium, and more particularly to a recording apparatus of which the recording medium transporting unit is contrived.
A conventional large printer as a recording apparatus is made up of a sheet supply unit for supplying a rolled sheet as a recording medium, a printing unit for recording information on the supplied rolled sheet, and a sheet discharge unit for discharging the printed rolled sheet, and those units are disposed in this order from the upper part. To use such a large printer as a large ink jet printer, the user pulls out the leading end of the rolled sheet that is contained in the sheet supply unit. The user moves the leading end of the rolled sheet on and along a flat, sheet feeding guide serving as a sheet transporting surface, puts it between a sheet feeding roller and a follower roller, and starts the printer.
The ink jet printer ejects ink drops from the nozzle orifices of a printing head to record information on the rolled sheet, while feeding the rolled sheet onto the platen by rotating the sheet feeding roller. Then, the printer rotates a sheet discharging roller to discharge outside the rolled sheet on and along a flat, sheet discharging guide serving as a sheet transporting surface.
In the printer, it is a common practice to use for the recording medium, rolled sheets in which fibers are extended in a sheet transporting direction, namely, the sub-scan direction, and which are arranged side by side in a direction perpendicular to the sheet transporting direction, i.e., the main scan direction. At the completion of the printing on the rolled sheet, the rolled sheet is in a water-absorbing state since ink has been attached thereto. In this state, the rolled sheet is made wavy, so-called cockling, in a direction in which the binding of fibers is weak, namely, the main scan direction.
In the conventional printer, the sheet transporting surface ranging from the platen to the sheet discharging guide is flat. Therefore, when the cockling grows, there is a fear that the recording surface of the rolled sheet is rubbed by the printing head located above the platen.
As shown in FIG. 22A, the cockling may be depicted by traces which slope down toward an incomplete printing portion (hatched area in FIG. 22A) of the rolled sheet R of which the printing is not yet completed at the side edges of the rolled sheet near that portion of the rolled sheet. As shown, the ridge lines and the root lines of the cockling converge toward the incomplete printing portion of the rolled sheet at the side edges of the rolled sheet R. As a result, as shown in FIG. 22B, the rolled sheet rises in the vicinity of the incomplete printing portion to possibly rub against the printing head.
Accordingly, an object of the present invention is to provide a recording apparatus which is capable of preventing the cockling from occurring in the recording medium.
(1) According to the invention, there is provided a first recording apparatus having a feeding unit for storing and feeding a recording medium, a recording unit for recording information on the recording medium having been fed from the feeding unit, and a discharging unit for discharging outside the recording medium having been transported through the recording unit, the improvement being characterized in that a warping part for warping the recording medium is formed on a guide member which is disposed downstream of the recording unit and inclined in a gravity direction.
With such an arrangement, even if the cockling occurs in a recording medium of which the recording has been completed in the recording unit, the recording medium may be bent in a direction orthogonal to directions in which the cockling occurs. Accordingly, stress acting to spread the recording medium in directions of the cockling generation is generated at the bending part. As a result, there is completely eliminated a chance of generating the cockling in the recording medium.
(2) In the recording apparatus according to (1), the warping part includes a flat surface which is uniform over a direction orthogonal to the transporting direction of the recording medium. With this technical feature, the recording medium may be transported on and along the warping part in flat state, whereby preventing the re-occurrence of the cockling.
(3) In the recording apparatus according to (1) or (2), a suction unit for sucking the recording medium is disposed near the warping part. With this feature, the recording medium warped by the warping part is easy to come in contact with the suction unit. As a result, the suction performance of the recording medium is improved.
(4) In the recording apparatus according to any of (1) through (3), a recording medium discharge roller for discharging the recording medium is disposed immediately after the warping part. This feature enables the recording medium of which the cockling is completely removed to be smoothly discharged outside.
(5) In the recording apparatus according to any of (1) through (4), the warping part includes an inclined recording medium transporting surface for changing a transporting direction of the incoming recording medium to warp the recording medium. With this feature, the recording medium may be transported along the flat surface and then the inclined surface. Accordingly, the recording medium is easily warped.
(6) According to another aspect of the invention, there is provided a second recording apparatus having a feeding unit for storing and a feeding recording medium, a recording unit for recording information on the recording medium having been fed from the feeding unit, and a discharging unit for discharging outside the recording medium having been transported through the recording unit, the improvement being characterized in that a warping part for warping the recording medium and supporting parts for supporting both side edges of the recording medium warped by the warping part are formed on a guide member disposed downstream of the recording unit.
With such an arrangement, even if the cockling occurs in a recording medium of which the recording has been completed in the recording unit, the recording medium may be bent in a direction orthogonal to directions in which the cockling occurs. Accordingly, stress acting to spread the recording medium in directions of the cockling generation is generated at the bending part. As a result, there is completely eliminated a chance of generating the cockling in the recording medium. Further, both side ends of the boundary region between a not yet recorded portion suffering from the cockling and a recorded portion are lifted by the supporting parts. The recording medium sags at a part of the recording medium between the supporting parts by its weight, and is concavely curved. Accordingly, there is no chance that the recording medium rises in the boundary region of the recording medium.
(7) In the recording apparatus according to (6), the warping part includes an inclined, recording medium transporting surface for changing a transporting direction of the incoming recording medium to warp the recording medium, and the supporting parts have support surfaces which are flush with the recording medium transporting surface. With this feature, the recording medium may be transported along the flat surface and then the inclined surface. Accordingly, the recording medium is easily warped. Further, the recording medium may be smoothly transported from the recording medium transporting surface to the support surfaces. Accordingly, the recording medium may be concavely curved with good reliability.
(8) In the recording apparatus according to (6) or (7), a plurality of the supporting parts are arranged such that a length of the arrangement of the supporting parts is somewhat narrower than each of the recording mediums of the different widths. Therefore, even if the recording medium is changed to another kind of recording medium, both side edges of the recording medium can be supported with good reliability.
(9) In the recording apparatus according to (7) or (8), an auxiliary supporting part for supporting both side edges of the recording medium is provided on the recording medium transporting surface. With such the arrangement of an auxiliary supporting part, even when the recording medium having a large rigidity is used and is not concavely curved between the supporting parts, the recording medium may be convexly curved by the auxiliary supporting part. As a result, the recording medium may be concavely curved between the auxiliary supporting part and the supporting parts.
(10) In the recording apparatus according to any of (5), (7), (8) and (9), the inclined recording medium transporting surface of the warping part is formed by bending a plate like member in a direction orthogonal to the medium transporting direction. This feature provides the warping part having a simple structure, and hence a simple manufacturing process of manufacturing the recording apparatus.
(11) In the recording apparatus according to any of (1) through (10), the warping part is warped so that the recording surface of the recording medium is concavely curved. Therefore, the recording medium suffering from the cockling may be pressed against the recording medium transporting surface, to thereby perfectly preventing the rubbing of the recording medium against the recording head.
(12) In the recording apparatus according to (11), an inclination angle of the inclined, recording medium transporting surface of the warping part is 6xc2x0. If the inclination angle is so selected, no crease is formed in the recording medium, and the formation of the cockling in the recording medium is completely removed.
(13) In the recording apparatus according to (1), the warping part includes a first sheet transporting surface ascendingly inclined and a second sheet transporting surface descendingly inclined with respect to the sheet transporting path of the recording medium.